***Login to the Forum here ***

Support FSC and see no ads! - Click Here
Page 1 of 2 12 LastLast
Results 1 to 20 of 25

1998 5.7 csfi starts then dies immediately

This is a discussion on 1998 5.7 csfi starts then dies immediately within the Technical / Maintenance forums, part of the General Discussion category; Working on a 1998 chevy 1/2 ton with 5.7 csfi, "spider" setup. The truck will fire up then run for ...

  1. #1
    Registered User
    Join Date
    Oct 2006
    Location
    az
    Posts
    12

    1998 5.7 csfi starts then dies immediately


    Support FSC and see no ads! - Click Here
    Working on a 1998 chevy 1/2 ton with 5.7 csfi, "spider" setup. The truck will fire up then run for a second then die. Definetly a fuel problem , if you pour some gas in intake it will run for a much longer time , until the gas is used up. Fuel pressure goes up to 60 psi, goes down to 55 or 56 when cranking. After it runs for one second, and the engine dies, then the fuel pressure drops to zero within 10 seconds or so. I have already replaced the fpr. I thought for sure that was the culprit. Is it possible it could be the pump, even though pressure is good? Why would it bleed down that quick. I do not think that is normal is it? I thought the system remains pressurized for a little longer than 10 seconds.
    Well please help.

    Oh yeah and who were the engineering geniuses that came up with this fuel system anyway?

    Tom

  2. #2
    Registered User
    Join Date
    Oct 2006
    Location
    az
    Posts
    12

    Re: 1998 5.7 csfi starts then dies immediately

    forgot to add the fuel filter was replaced.

  3. #3
    Registered User
    Join Date
    Feb 2006
    Location
    UT
    Posts
    224

    Re: 1998 5.7 csfi starts then dies immediately

    I'm not real intimately familiar with my Suburban, yet. From what My Explorer uses a very similar fuel delivery system. I played around with it once and found that that system requires at least 25 psi for the engine to run. Anytime the fuel pressure would drop below that, the engine would sputter and stall. Same kind of thing here, anytime the fuel pressure drops below a certain value, the engine will stumble and stall. You have to find out why the fuel pressure is dropping off. Does the pump stop running? I've heard mention around here of an oil pressure sensor that, if the computer doesn't detect the correct oil pressure, it will shut the pump off and kill the engine. Have you got access to a scanner that you could hook up and figure out why the computer is shutting the pump off?

  4. #4
    Registered User
    Join Date
    Oct 2006
    Location
    az
    Posts
    12

    Re: 1998 5.7 csfi starts then dies immediately

    The pressure doesnt drop until the engine quits running (no oil pressure). Although maybe i should double check this by monitoring the voltage going to the fuel pump to make sure power isnt being cut off to the pump.
    I also checked for codes and there are no codes present.
    I have done some searching in this forum and read that there is a check valve in the pump that could be stuck open. Maybe the pressure is good at first crank then after the fuel starts to flow back it drops just enough to not go through the injectors? Or maybe the pressure dropping has nothing to do with the engine dying.
    any other suggestions?

  5. #5
    Registered User
    Join Date
    Oct 2004
    Location
    Woodstock Ontario Canada
    Age
    38
    Posts
    8,263

    Re: 1998 5.7 csfi starts then dies immediately

    Since its a 1998, I am wondering if the VATS (vehicle anti theftsystem) is acting up.

    teh VATS on teh 1998+ trucks will kill the injectors about 4 seconds after starting.

    Maybe you need a security relearn???

    peace
    PAuly
    97 GMC 2wd RCSB 5.7, s10 2700 footstall, Hooker 24621hkr LT's , 2.5" cats dual 4"pipes exit B4 pass. side tire, custom driveshaft 3.42 G80 FIPK MAF descreen GM/Mercruiser Marine intake manifold 29lb LS2(EV6) injectors Ed Wright PCM(best mod), LT4 KM 14.8@94mph 2.007 4000lbs 122mph

  6. #6
    Registered User
    Join Date
    Oct 2006
    Location
    az
    Posts
    12

    Re: 1998 5.7 csfi starts then dies immediately

    I have read about that too. Is that something that will out of the blue , all of a sudden happen ?
    the owner said it would hesitate on acceleration from a stop before all this happened. But that doesnt mean it couldnt be the security system.

  7. #7
    Registered User
    Join Date
    Jun 2005
    Location
    Texas
    Age
    56
    Posts
    796

    Re: 1998 5.7 csfi starts then dies immediately

    have the codes read,if its a passlock problem youll have codes in the pcm,passlock module or both.post the results.

  8. #8
    This is All You'll See Boosted-Z71's Avatar
    Join Date
    Mar 2002
    Location
    Greentown, Indiana
    Age
    52
    Posts
    1,097

    Re: 1998 5.7 csfi starts then dies immediately

    Does the security light flash or stay on in the IP cluster? I think I would do the VATS relearn. Has there been any work done to the ECM recently, or unplugged for a length of time?
    If none of the above apply, I would be looking at Fuel pressure very closely, these CSFI systems are very picky on FP.
    Also was there fuel in the pockets / floor of the lower intake, the csfi body is known to leak & this would cause the quick depressuring that you are seeing.

    Boosted
    98 Ext Cab Chevy-Z71, 5.7, Built Front to Back. 87 SB 5.7 Vortec / TBi Combo, Getting Faster Everyday

  9. #9
    Registered User
    Join Date
    Oct 2006
    Location
    az
    Posts
    12

    Re: 1998 5.7 csfi starts then dies immediately

    when i had the upper intake off I hooked up the fuel lines and turned the key on to pressurize the system and make sure there were no leaks after i installed the fpr.
    I am leaning toward replacing the pump but I heard this is the year gm had a module setup in the gas tank, so you have to spend $350 (aftermarket) to replace the pump since it comes with sending unit. Now the guy that owns this says he replaced the pump before, with a pump from the junkyard. Yeah I know.. anyway the way he put it sounds like the pump was a servicable part, not part of a "module". Not really sure since i have never seen this super duper fuel pump setup before. I guess it is all one piece and you cant just replace the fuel pump, or can you? The dealer says in 1998 is when it was changed to the modular setup.

    thanks for all the help so far, i will double check the security on this too.

    Tom

  10. #10
    This is All You'll See Boosted-Z71's Avatar
    Join Date
    Mar 2002
    Location
    Greentown, Indiana
    Age
    52
    Posts
    1,097

    Re: 1998 5.7 csfi starts then dies immediately

    Tom, the 98 pumps do come as a unit, but they can be taken apart & the pump repalced. Its a pain & I did it on my truck to put a higher capacity pump in. There is a company on E-bay that sells these cheaper, and they sell parts to fix the units without replacing the entire unit. Pauly will know the company for sure, maybe he will reply or you could PM him about it. I will keep looking for you, I thought I had the sellers name saved.

    Boosted
    98 Ext Cab Chevy-Z71, 5.7, Built Front to Back. 87 SB 5.7 Vortec / TBi Combo, Getting Faster Everyday

  11. #11
    Registered User
    Join Date
    Oct 2006
    Location
    az
    Posts
    12

    Re: 1998 5.7 csfi starts then dies immediately

    Well i think we eliminated the fuel pump as a possibility. There was another truck there, same year make and model. we connected a fuel line from the pressure line of the truck that runs, and connected that to the main pressure line to the truck that doesnt run. used a jumper wire at the fuel pump relay to keep the pump running, then made sure there was 60 psi which there was and it would still do the same thing. And the pressure would stay up after engine stopped running.
    So apparently the fact that it leaks down after the engine stops has nothing to do with the truck dying.
    And there is a security light on, but no codes came up on the scanner tool. He said the security light has been on for months.
    I am now thinking about replacing the fuel injector assembly. Maybe something clogged it up? But I was wondering if there was a way to verify whether the injectors are receiving any power or if they are being shut off. Can I just use a volt meter and put it across a pair of the wires going to an injector? Or what do you need to verify this?

    Thanks for all your help,

    Tom

  12. #12
    Registered User
    Join Date
    Oct 2006
    Location
    az
    Posts
    12

    Re: 1998 5.7 csfi starts then dies immediately

    is there anything that would shut off power to the injectors, and is there anyway to find out if this has happened?

    Thanks

    Tom

  13. #13
    1972 Chevy Beauville Diamond Jim's Avatar
    Join Date
    Feb 2004
    Location
    coastal NC
    Posts
    1,460

    Re: 1998 5.7 csfi starts then dies immediately

    Oil pressure sending unit or no oil pressure!
    Diamond Jim
    98 Burb, 5.7L, 2500LS, 4X4; 80 GMC 383, Ĺ, Long bed; 74 Dually Flatbed 350; 73 Short bed 350 4X4; 41 Chevy Master Deluxe, 327/375hp Rochester FI; 89 Fleetwood Bounder, 2 ton Chevy Chassis, 454/TH425

  14. #14
    This is All You'll See Boosted-Z71's Avatar
    Join Date
    Mar 2002
    Location
    Greentown, Indiana
    Age
    52
    Posts
    1,097

    Re: 1998 5.7 csfi starts then dies immediately

    I think you need to do the security re-learn, I had similar problems with an ECM re-flash. I will look for the procedure for you & post it. I got a ton of junk to look through.

    Boosted
    98 Ext Cab Chevy-Z71, 5.7, Built Front to Back. 87 SB 5.7 Vortec / TBi Combo, Getting Faster Everyday

  15. #15
    Registered User
    Join Date
    Oct 2006
    Location
    az
    Posts
    12

    Re: 1998 5.7 csfi starts then dies immediately

    Is the procedure leave key in run position for 10 minutes, turn to off for 10 seconds, then repeat that 2 more times for a total of 3 cycles?
    Last edited by tdg455; 11-13-2006 at 10:21 AM.

  16. #16
    This is All You'll See Boosted-Z71's Avatar
    Join Date
    Mar 2002
    Location
    Greentown, Indiana
    Age
    52
    Posts
    1,097

    Re: 1998 5.7 csfi starts then dies immediately

    Here you go

    Auto Learn Passlock Procdure
    (This procedure should take 31 minutes to complete)

    1. Turn the ignition switch to the RUN position, (Not the Crank Position)
    2. Turn the ignition switch to CRANK position, release to RUN position
    3. Observe the Security telltale for approximately 10 minutes
    4. After the ign switch has been in the RUN position for approximately 10 minutes the security telltale will transition from ON to OFF.
    5. Repeat Steps #1 through #4 two more times
    6. After three consecutive cycles of the ignition switch are successfully completed, the vehicle will learn the new component on the next ignition cycle from the OFF position to the CRANK to the RUN position. The vehicle will then start.
    7. Itís only necessary to do this complete procedure one time. If for some reason the vehicle tries to start, disconnect the negative battery lead for 30 seconds and start the procedure over.

    Boosted
    98 Ext Cab Chevy-Z71, 5.7, Built Front to Back. 87 SB 5.7 Vortec / TBi Combo, Getting Faster Everyday

  17. #17
    1972 Chevy Beauville Diamond Jim's Avatar
    Join Date
    Feb 2004
    Location
    coastal NC
    Posts
    1,460

    Re: 1998 5.7 csfi starts then dies immediately

    This is the way I have always done it. It works for me. A little different in that you do try to turn the engine over.

    The typical 1998+ Car and Truck Passkey/Antitheft relearn procedure is this:

    1. Disable your headlamps. Attempt to start the vehicle. Vehicle may or may not 'fire' and quit. Some vehicles will not engage the starter. This is normal. DO NOT TURN OFF KEY YET !!

    2. Leave the key in the "on" position, until the 'security' light goes out or quits alternately flashing between "Security" and "Battery". This relearn period always takes 10 minutes. How long does this take ? 10 minutes. How long do I have to wait ? 10 minutes.

    3. After security light is no longer displayed, shut the key off ! Wait 5-10 seconds and repeat the above procedure (steps 1 through 3) another two completed times for a total of 3 start-relearn-attempts, remembering to shut the key off between each 10 minute relearn procedure. This will take 30 minutes--no less. If the 4th start attempt fails to start the vehicle you did one relearn step (or all of them incorrectly). If you left your headlamps on until the battery went dead and voltage dropped below 10.5 volts, no amount of relearn attempts will be learned !!

    Don't read too much into this. Most people cannot seem to grasp the simplicity of this relearn procedure.
    Last edited by Diamond Jim; 11-13-2006 at 05:05 PM.
    Diamond Jim
    98 Burb, 5.7L, 2500LS, 4X4; 80 GMC 383, Ĺ, Long bed; 74 Dually Flatbed 350; 73 Short bed 350 4X4; 41 Chevy Master Deluxe, 327/375hp Rochester FI; 89 Fleetwood Bounder, 2 ton Chevy Chassis, 454/TH425

  18. #18
    Registered User
    Join Date
    Oct 2006
    Location
    az
    Posts
    12

    Re: 1998 5.7 csfi starts then dies immediately

    I was wondering, is this something that would happen without changing anything on the truck. I thought this procedure was needed after you would replace an ignition switch or something. I will go ahead and try it though.

    Thanks

    Tom

  19. #19
    This is All You'll See Boosted-Z71's Avatar
    Join Date
    Mar 2002
    Location
    Greentown, Indiana
    Age
    52
    Posts
    1,097

    Re: 1998 5.7 csfi starts then dies immediately

    I have only seen this happen on an ECM replacement / swap. Was it running when it came to you? The prcedure I gave you I got from a tuner that I dealt with & had a similar problem after an ECM re-flash. If the security light stays out after the procedure & it still doies not start I would start checking for voltage at the injectors, You could have an ECM going bad. We just replaced one on a S-10 4.3 that was diagnoised with every other problem in the world by 2 dealerships & a couple independent mechanics. It had 2 complete tune-ups done, dist. replaced, injectors replaced, fuel pump, gas tank replaced, (still trying to figure that one out) etc. We bought the truck dirt cheap & started looking at what they had not done. I had an old ECM so we copied the 4.3 program & flashed the replacement ecm. Truck runs great all the symptoms are gone.

    Good luck these vortec poppet systems are a pain!

    Boosted
    98 Ext Cab Chevy-Z71, 5.7, Built Front to Back. 87 SB 5.7 Vortec / TBi Combo, Getting Faster Everyday

  20. #20
    Registered User
    Join Date
    Oct 2006
    Location
    az
    Posts
    12

    Re: 1998 5.7 csfi starts then dies immediately

    Well one thing I wanted to do was check for voltage going to the injectors. It seems to me if the injectors were not working then why would it fire up to begin with? Unless the injectors leak a little and the engine fires up on that. I figured i should check voltage going to injectors first, before pulling them out. But anyway how much voltage should be at the injectors? I see a bunch of pink wires in there, i assume those are the hot wires and the other colors are ground? Would i put my volt meter across a pair of wires going to each injector?
    I dont want to waste anymore time and money on this thing. I already screwed up replacing the fpr. Although at least that is one more thing he doesnt have to worry about later.
    The whole leak down in pressure thing through me off course at first. Turns out it isnt the cause.

    Thanks for the help

    Tom

 

 
Page 1 of 2 12 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •